I know exactly what you're talking about. I see the same crazy militant people. It's very common place for people to argue that owning guns is about preventing government tyranny and overreach. It doesn't matter how much I have tried to talk to those people... but that is their view... and that view is completely ignorant and not based in reality. Well armed people like themselves are not capable of a revolution, they are not capable of defeating the US military, and they are the most likely culprit in America, to support some form of government tyranny and overreach.
The Trump presidency is not going to end well, and I often do wonder what such people are going to do. Predicting they will try to take to the streets is highly likely. They can go out with their guns, open carry, and rally... try to have a march... neo nazis could get involved again, antifa show up, and we know how that is going to play out.
No matter what they think, they are not going to save the Trump presidency nor can they get the trade deals they want by waving guns around.
As for Trump declaring martial law or trying to stop or delay the next election, it really wouldn't surprise me if he started openly saying and arguing for such things. He has already said a number of things about wanting to be president for life, so nothing would surprise me. I have seen some other posters predict he might try to flee to Russia for sanctuary.
It's definitely going to get a lot worse for Trump politically and economically. Trump doing, saying, or trying anything in the future, really wouldn't surprise me. His craziest supporters will always back him. I have seen them on TV literally crying for him, and for how hard he tries to do the right thing but the deep state is always in his way.
I really do worry for America. Trump is going to be gone eventually, but the GOP needs to figure out what to do with these elements in their party and their base. It's actually very scary and concerning.